BB spindle length?

[goshow]

Hi all, Is there a guide / science behind measuring the required spindle length?
I'm rebuilding a 92 Orange and the BB i've fitted looks a bit long. "fit a shorter one" I hear you say!! Obviously I'm going to but thought I'd ask to see if there was a guide / method for measuring the correct size.

Thanks in advance.

 

[Imlach]

What cranks will you be running?

 

[goshow]

What cranks will you be running?

M900 XTR.
It's for a 92 Orange Aluminium Elite.

 

[Imlach]

What's the current spindle length?

 

[Imlach]

With that crank it should be like 107mm
For wider stay bike's probably 110.

 

[goshow]

What's the current spindle length?

Just had my verniers on it, 127.7mm

 

[Imlach]

Just had my verniers on it, 127.7mm

I use 127 on my Surly's because they've got pretty fat stays, 107 to 110 should be perfect for you.

 

[Imlach]

XTR m900 should already have a wider q factor, so going above 113 might make them sit too far out for your liking

 

[goshow]

XTR m900 should already have a wider q factor, so going above 113 might make them sit too far out for your liking

That's brilliant, thanks for your help. #LEGEND

 

[FluffyChicken]

107 is the standard M900 bottom bracket for a 47.5 chainline at the time.

113 if you need to go for the 50mm chainline

For a prestige or clockwork, the. 107 is your length, with recessed cups too.

Alu-O/Elite should be able to use the same as they only use middle diameter front mech bands. That and its what I use on mine.